1. Field of the invention
This invention relates in general to seals for wellheads, and in particular to a U-shaped seal having a rib for protecting the sealing band during the installation of the seal.
2. Description of the Prior Art
In one type of well completion, a wellhead or inner tubular member will be secured to the upper end of the well. The inner tubular member has an external shoulder and an external sidewall surface. An outer tubular member inserts down over the inner tubular member to connect pressure control equipment located above. The outer tubular member has an internal sidewall surface.
An annular space exists between the two sidewall surfaces. A seal member locates in this annular space to seal the tubular members. One type of seal has inner and outer legs or walls spaced radially apart. Each wall has a sealing band on its upper end that engages one of the sidewall surfaces. The seal is metal, and the sealing band is coated with a material to enhance sealing.
One disadvantage of this system is that when the seal is inserted over the inner tubular member, the inner sealing band will rub on the external sidewall surface as the seal is pushed downward against the shoulder. Also, when the outer tubular member inserts over the inner tubular member, the outer sealing band will rub against the internal sidewall surface during the insertion movement. The rubbing causes some of the coating to wear away.